A Palestinian man carries an injured child following an Israeli airstrike on a UN school in Rafah, in the southern Gaza Strip on August 3, 2014.

The United States has strongly condemned a deadly Israeli airstrike on a United Nations school sheltering about 3,000 displaced Palestinians in southern Gaza, saying it is “appalled” by the “disgraceful” attack.

On Sunday, Israel launched another attack on a UN-run school in the town of Rafah, leaving at least 10 people dead and about 30 others injured. This was the third time in 10 days that a UN school has been targeted by the Zionist forces in their nearly month-long offensive against the besieged Gaza Strip.

The State Department in a statement issued on Sunday denounced the attack, noting that the school had been designated a protected location.

“The United States is appalled by today’s disgraceful shelling outside an UNRWA school in Rafah sheltering some 3,000 displaced persons, in which at least 10 more Palestinian civilians were tragically killed,” State Department spokeswoman Jen Psaki said.

“The coordinates of the school, like all UN facilities in Gaza, have been repeatedly communicated to the Israeli” forces, Psaki stated.

“We once again stress that Israel must do more to meet its own standards and avoid civilian casualties,” she added.

Earlier in the day, UN Secretary General Ban Ki-moon denounced the shelling of the school as “a moral outrage and a criminal act.”

“This madness must stop,” Ban said through his spokesman.

He added that the strike was “yet another gross violation of international humanitarian law” by Israel.

“This attack, along with other breaches of international law, must be swiftly investigated and those responsible held accountable. It is a moral outrage and a criminal act,” he said.

More than 1,850 Palestinians have been killed, including women and children, and over 9,300 others injured by the Israeli regime’s offensive against the coastal enclave despite pressure from the international community. The United Nations says over 80 percent of the fatalities in Gaza have been civilians.